Can you cite the relevant code? I've not seen a cable TV ground made at the mains service panel.
I just went out and double checked mine, and it's earth grounded at the distribution block where the cable enters the house, which is a good 25 feet from the service panel.
se
No, but it makes a difference if he (or anyone else reading this) decides to buy some input transformers.
se
Lynn, Gary Dahl, and anyone with experience with ribbon tweeters like the RAAL, or AMT tweeters like the Mundorf or Beyma TPL150
Lynn,
Have you been able to listen to or measure the RAAL ribbon tweeters you purchased at the RMAF? I keep wondering if these new ribbon/AMT tweeters have sonic and dispersion control capabilities that make them better suited as home audio tweeters when compared to compression drivers with horns.
How about building wider, shorter ribbon tweeters to improve vertical dispersion while maintaing the same area and efficiency from the latest N52 grade NdFeB magnets? Anyone have a 1" wide and 2" long ribbon tweeter?
I never owned a horn and don't expect Santa to bring one this Christmas.
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I've worked extensively with both the TPL and the normal Raal 140-15. Raal wins hands down in terms of effortless sounding highs that just seem to float in space. Hard to describe until you hear it. I wonder if the big Raven ribbons do the same trick, but have never been able to work with them or even hear them for that matter. I have not been as impressed with the Fountek or Aurum Cantus offerings.
Greg
Hi BudP,
As you know, Romy uses the "teardrop" high frequency ribbon made on special order from RAAL (pic 1). The teardrop ribbon is only 0.2" wide and optimized for the 8KHz Xover Romy uses.
RAAL's production 140-15D ribbon is 0.6" wide (pic 2) and designed for a LR4 slope at 1,600 Hz (pic 3). This seems low enough to cross to a high'ish efficiency 8" or 10" midbass. RAAL's measurements show this ribbon can reproduce 30K-40K Hz super sonics, and reaching these frequencies is an important spec to RAAL.
What if we built a ribbon that used 1" - 1.2" wide and 2" high Al foil to maintain efficiency of 100 db/watt with a 20KHz maximum frequency. Would this ribbon design be "better than" a compression+horn tweeter for horn challenged homes?
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I spent quite a bit of time with the Red Rose large system, designed and built by Bo Bingston. These had some 6 feet of bare ribbon, divided into 3 panels. I have long since forgotten the crossover point but I do believe it was startlingly low. They certainly did not lack for dynamics at any frequency. I had gotten involved, with AudioPrisms Vic Tiscareno, to provide a high performance matching autoformer. I do remember that it needed to handle 500 watts at 250 Hz, but I am pretty sure that was not the crossover point.
So, I know that large bare ribbons can be built, that will provide sensational sound. I can only begin to imagine what Alexanders native intelligence would bring to such a device. His ribbons do seem to be better controlled, with his unusual patterns stamped into the metal. Might just be the best thing ever and he did, at one time, hint to me that he was working on a full range system......
Bud
So, I know that large bare ribbons can be built, that will provide sensational sound. I can only begin to imagine what Alexanders native intelligence would bring to such a device. His ribbons do seem to be better controlled, with his unusual patterns stamped into the metal. Might just be the best thing ever and he did, at one time, hint to me that he was working on a full range system......
Bud
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I have a set of version 6 cabinets that i would consider parting with. Drivers and crossover could be included. They were just recently veneered in waterfall bubinga, but not yet finished (oil, varnish, whatever you choose).
If you consider yourself a newbie, I can assure you these cabinets were not easy to build. No, not at all.
If you consider yourself a newbie, I can assure you these cabinets were not easy to build. No, not at all.
What's the latest with the Benaroyas? Current crossover?
Hey all, this project is of very great interest to me, as I am putting together a system with TD15Ms + JBL 2441 2" compression drivers using the Brush-Wellman beryllium diaphragms. A crossover of ~700hz appeals to me, and my experience hearing other people's BW Be diaphragms in 2" JBL drivers makes me think it might reach high enough for my needs. What is the latest on the crossover? Has it changed substantially from the one posted on p. 731 of this thread?
I haven't decided what waveguide to use here, but I did find out from Martin Seddon that the AH-425 is available with 2" throat, so it can be used with the beryllium'ed alnico JBL drivers. That is appealing.
This isn't my first time building two-ways with 15" + 2" CD. I have made some TAD 2402 clones and become very accustomed to the big dynamics of that combination. I want that in a second system, and so far it's coming in at about half the TAD price for the parts. 2441 + BW Be is half the price of TAD TD-4001; AH-425 is half the price of TH-4001, etc.
Hey all, this project is of very great interest to me, as I am putting together a system with TD15Ms + JBL 2441 2" compression drivers using the Brush-Wellman beryllium diaphragms. A crossover of ~700hz appeals to me, and my experience hearing other people's BW Be diaphragms in 2" JBL drivers makes me think it might reach high enough for my needs. What is the latest on the crossover? Has it changed substantially from the one posted on p. 731 of this thread?
I haven't decided what waveguide to use here, but I did find out from Martin Seddon that the AH-425 is available with 2" throat, so it can be used with the beryllium'ed alnico JBL drivers. That is appealing.
This isn't my first time building two-ways with 15" + 2" CD. I have made some TAD 2402 clones and become very accustomed to the big dynamics of that combination. I want that in a second system, and so far it's coming in at about half the TAD price for the parts. 2441 + BW Be is half the price of TAD TD-4001; AH-425 is half the price of TH-4001, etc.
Was it over when the Germans bombed Pearl Harbor? It's not over till we say it's over!
How can it be over without pictures? How can it be over, when I'm starting to build a pair? Actually what I have is new TD15Ms in recycled 8 cu ft JBL cabinets (4846), JBL 2440s and constant directivity horns, and a couple of crossovers from other projects being reworked... but it's a start, and it's playing music! I was just starting to look into more appropriate crossovers, and was excited when someone directed me at this thread a couple of days ago.
So Gary, what's the status now? Done and loving it? Did you add a supertweeter?
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The Germans bombed Pearl Harbor?! The news stinks out here on the left coast. They haven't broadcast it yet! Something like this should be all over the place.
Dan
I saw Lynn's post somewhere in which he said that he wasn't happy with the low efficiency of the bass section. With this design, you are giving up 10-15 db on the horns. He was going to look at front horns... something, which I'm about to jump into
Yeah, the compression driver is 111 db, the woofer is about 98, so 13 difference. But sheesh, an honest 98db/1w/1m with real bass in ~6-8 cu ft. is pretty darn good.
I've got gigantic rear-loading horns with somewhat greater efficiency in the low end, and I love the sound, but a pretty modest triode amp will drive the Benaroya setup, and it can look almost normal in your living room. There's a place for it!
For me the place is in my workshop.